Answer / satya

For an induction motor we have
s= (Ns-Nr)/Ns
so slip can be negative in the region where the value of
rotor speed exceeds that of the synchronous speed. usually
while working as an induction motor the speed of the rotor
cant touch the synchronous speed. because as it does so
there will be no cutting of the flux lines by the rotor
conductors. so there will be no emf induced so no current ,
so no force and no torque.
but when the induction motor is run by an external
primemover over the synchronous speed now rotor speed
increases that of the Ns. so rotor emf E2> stator applied emf.
the induction motor now functions as an induction generator.

Answer / ankaraju

If the rotor is running more with respect to stator or
meachine synchronous speed called as negative slip.
OR
The injected or developed frequency in rotor is greater
than supply frequency.
significent:Induction motor acts as induction generetor.

Answer / tufail

It signifies that the motor is acting as a generator.

Answer / trupti

slip=(Ns-N)/Ns
wh Ns - sync speed
N - actual speed of rotor.
generally whn IM is acting as motor,rotor speed is always
less than Ns,but if it is acting as gen(a prime mover moves
rotor),N bcms gr8er than Ns.
hence 4m formula we can c that s bcms -ve.
it implies rotor is running faster than stator field.

Answer / niranajn

it indicates that the motor is generating

Answer / harish

if rotor speed is greater than stator speed then we get -ve
slip
slip speed =n(synhronous)-n(rotor)

Answer / rakesh kumar bharti

The slip can be negative when the induction motor works as a generator i.e
The Ns speed is less than the Nr speed.the negative slip makes the electromagnetic torque negative during regeneration on generating mode.

Answer / m.kaleem akram

its mean induction machine is working as a generator....because in case of induction motor slip is always positive.

Answer / gajendra patel

In case of induction motor rotor speed is always less then synchronous speed so its convert electrical to mechanical so its called motor and another case rotor.speed is more than synchronous speed then slip is negative (help of primemover) and thus its produced electricity so its called generator

Answer / sashank

If Nr speed is greater than Ns that is called - ve slip, if Nr speen is equal to Ns that is called zero slip and Nr is less than Ns that is called +ve slip.....

Why we use a shunt capacitor or synchronizing Motor To Improve a Power factor pls reply me in this mail dinesh_elect_eng@yahoo.com

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